On Wed, Jan 09, 2019 at 04:51:17PM -0800, Sean Christopherson wrote: > The conversion to use a structure for mmu_notifier_invalidate_range_*() > unintentionally changed the usage in try_to_unmap_one() to init the > 'struct mmu_notifier_range' with vma->vm_start instead of @address, > i.e. it invalidates the wrong address range. Revert to the correct > address range. > > Manifests as KVM use-after-free WARNINGs and subsequent "BUG: Bad page > state in process X" errors when reclaiming from a KVM guest due to KVM > removing the wrong pages from its own mappings. > > Reported-by: [email protected] > Reported-by: Mike Galbraith <[email protected]> > Reported-by: Adam Borowski <[email protected]>
Reviewed-by: Jérôme Glisse <[email protected]> > Cc: Christian König <[email protected]> > Cc: Jan Kara <[email protected]> > Cc: Matthew Wilcox <[email protected]> > Cc: Ross Zwisler <[email protected]> > Cc: Dan Williams <[email protected]> > Cc: Paolo Bonzini <[email protected]> > Cc: Radim Krčmář <[email protected]> > Cc: Michal Hocko <[email protected]> > Cc: Felix Kuehling <[email protected]> > Cc: Ralph Campbell <[email protected]> > Cc: John Hubbard <[email protected]> > Cc: Andrew Morton <[email protected]> > Cc: Linus Torvalds <[email protected]> > Fixes: ac46d4f3c432 ("mm/mmu_notifier: use structure for > invalidate_range_start/end calls v2") > Signed-off-by: Sean Christopherson <[email protected]> > --- > > FWIW, I looked through all other calls to mmu_notifier_range_init() in > the patch and didn't spot any other unintentional functional changes. > > mm/rmap.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/rmap.c b/mm/rmap.c > index 68a1a5b869a5..0454ecc29537 100644 > --- a/mm/rmap.c > +++ b/mm/rmap.c > @@ -1371,8 +1371,8 @@ static bool try_to_unmap_one(struct page *page, struct > vm_area_struct *vma, > * Note that the page can not be free in this function as call of > * try_to_unmap() must hold a reference on the page. > */ > - mmu_notifier_range_init(&range, vma->vm_mm, vma->vm_start, > - min(vma->vm_end, vma->vm_start + > + mmu_notifier_range_init(&range, vma->vm_mm, address, > + min(vma->vm_end, address + > (PAGE_SIZE << compound_order(page)))); > if (PageHuge(page)) { > /* > -- > 2.19.2 >
